ROCHESTER — The man killed during an altercation that ended in a vehicle on Sylvain Street late Sunday night died of a single gunshot wound to the chest, according to the New Hampshire Attorney General’s Office.

The manner of Richard Dumont’s death is considered a homicide, according to a press release from the AG’s office issued late Wednesday afternoon, and his autopsy Tuesday confirmed the cause of death as the wound to the chest.

There has not been an arrest made in the case and the AG’s office described the investigation as ongoing.

Dumont, 37, of Rochester, was shot and killed inside a vehicle. Neighbors described a loud argument inside a car stopped at Roy Street, with men shouting inside the vehicle as it crossed Washington Street. The altercation ended with gunshots and a terrifying scene unfolding on Sylvain Street.

Before gunshots rang out, a neighbor called 911 to alert authorities of the loud argument. As neighbor Paul Carrier, of 32 Washington St., was dialing police, he heard gunshots go off just outside his home.

A second neighbor to Carrier, who lives across the street from him, said her son heard two gunshots fired just feet from their home.

The shooter, who has not yet been named by authorities, was allegedly giving Dumont CPR when police arrived.

Carrier said police arrived within minutes and had weapons drawn.

Dumont’s 14-year-old son described the two as “the best of friends” Monday morning as he visited the site of the shooting.

However, on Tuesday, a woman who identified herself as a family member, disputed that fact saying the two men, both plumbers, were only coworkers.

That woman could not be reached by phone Tuesday or Wednesday for further comment.

No additional information beyond the autopsy report has been released, and there is no time frame for information given by state authorities at this time.